取当前字符串中第k个单词（简单）

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题目：获取当前字符串中第k个单词，如：" you are the best , so you can make it?"，第9个单词为 "it" ; "a a a b , df bb",第5个单词为"df"

思路：过滤非字母字符，找到第k个单词首位置，依次复制到首个非字母字符出现

c语言具体实现如下(IDE DEVC++ 5.7)：

//the Kth word#include<stdio.h>#include<stdlib.h>int is_letter(char a){if((a <= 'z' && a >= 'a')||(a <= 'Z' && a >= 'A'))return 1;elsereturn 0; }char* kth_word(char *str,char *result,int k){char *p,*q,*r;int count = 0,i=0;p = str;while(*p != '\0'){while(!is_letter(*p))//过滤非字母字符 p ++;q = p;//获取单词首字母 if(count == k-1){//找到第k-1个单词末尾位置while(is_letter(*q))result[i++] = *(q++);result[i] = '\0';break;/*指针法，保存单词首地址 result = r = q;//r用来保存单词首地址 while(is_letter(*q)) {result = q++;result ++;}*result = '\0';//result末尾元素置'0' 即截断并获取单词 result = r;break;*/}if(is_letter(*p) && !is_letter(*(p+1)))//统计单词数 count ++;p ++;}return result;}int main(){char a[] = " You are the best , so you can make it?";char b[] = "a t a b , df bb";char *r;puts(kth_word(a,r,1));puts(kth_word(a,r,5));puts(kth_word(a,r,9));puts(kth_word(b,r,2));puts(kth_word(b,r,5));return 0;}

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